{"id":896,"date":"2008-03-17T10:42:00","date_gmt":"2008-03-17T09:42:00","guid":{"rendered":"https:\/\/kids.esa.int\/a_swirling_atmospheric_sink_on_venus\/"},"modified":"2026-10-08T00:33:30","modified_gmt":"2026-10-07T22:33:30","slug":"a_swirling_atmospheric_sink_on_venus","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fr\/a_swirling_atmospheric_sink_on_venus\/","title":{"rendered":"Un \u00e9vier atmosph\u00e9rique tourbillonnant sur V\u00e9nus"},"content":{"rendered":"
\n

Imaginez une plan\u00e8te dot\u00e9e de deux tuyaux d'\u00e9coulement, l'un au Nord et l'autre au Sud. Chaque \u00e9vacuation s'accompagne d'un tourbillon de gaz atmosph\u00e9riques qui tournoient \u00e0 grande vitesse alors qu'ils d\u00e9valent vers la surface. A en croire la sonde de l'ESA, Venus Express, c'est pr\u00e9cis\u00e9ment ce qui semble se produire sur la plan\u00e8te soeur de la Terre, V\u00e9nus.<\/p>\n<\/div>\n

L'explorateur robotique europ\u00e9en est en orbite autour de cette plan\u00e8te depuis le 11 avril 2006. Les pr\u00e9c\u00e9dentes observations montraient un ph\u00e9nom\u00e8ne obscur semblable \u00e0 un ouragan (appel\u00e9 vortex) du c\u00f4t\u00e9 du p\u00f4le Sud. Une structure nuageuse similaire avait d\u00e9j\u00e0 \u00e9t\u00e9 rep\u00e9r\u00e9e au p\u00f4le Nord.<\/p>\n

\"The
L'\u0153il de l'ouragan<\/figcaption><\/figure>\n

Depuis, Venus Express a observ\u00e9 le p\u00f4le Sud de V\u00e9nus en permanence et elle a pu constater que le \u201ctourbillon\u201d est pour le moins changeant. Le 26 f\u00e9vrier 2007, il avait la forme d'un sablier. Vingt-quatre heures plus t\u00f4t, il \u00e9tait presque circulaire. D'autres fois encore, il est de forme ovale (comme un oeuf). De toute \u00e9vidence, il change de forme tr\u00e8s rapidement.<\/p>\n

Qu'est-ce qui provoque ce vortex larde de 2000 km ? Gr\u00e2ce \u00e0 Venus Express, nous avons pu d\u00e9couvrir que son centre est plus chaud que les zones alentours. Comme pour l'oeil de l'ouragan, cette r\u00e9gion plus chaude indique l'endroit o\u00f9 les gaz atmosph\u00e9riques se d\u00e9placent vers le bas, cr\u00e9ant ainsi une d\u00e9pression au sommet des nuages.<\/p>\n

\u201cL'\u00e9norme vortex ressemble \u00e0 ce que vous voyez dans votre baignoire apr\u00e8s avoir retir\u00e9 la bonde,\u201d explique Giuseppe Piccioni, scientifique travaillant sur Venus Express.<\/p>\n

Les scientifiques pensent que le dioxyde de carbone dans l'atmosph\u00e8re est chauff\u00e9 par le Soleil au niveau de l'\u00e9quateur. Le gaz monte, puis se d\u00e9place vers le p\u00f4le. Il redescend dans les r\u00e9gions polaires, g\u00e9n\u00e9rant cette \u201c\u00e9vacuation\u201d atmosph\u00e9rique.<\/p>","protected":false},"excerpt":{"rendered":"

Imagine a planet with two drains, one in the north and the other in the south. Each drain features a whirlpool of atmospheric gases which are swirling around at high […]<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"esa_banner_image":"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2008\/03\/venus_s_polar_vortex2\/18246846-2-eng-GB\/Venus_s_polar_vortex.jpg","esa_banner_description":"Venus's polar vortex","esa_banner_credit":"ESA\/VIRTIS\/INAF-IASF\/Obs. de Paris-LESIA\/Univ. of Oxford","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2008\/03\/Venus_s_polar_vortex2","esa_external_url":"","esa_external_new_window":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":true},"categories":[10,11,12],"tags":[],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-896","post","type-post","status-publish","format-standard","hentry","category-learn","category-our-universe","category-planets-and-moons"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/896","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/comments?post=896"}],"version-history":[{"count":4,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/896\/revisions"}],"predecessor-version":[{"id":4726,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/896\/revisions\/4726"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/media?parent=896"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/categories?post=896"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/tags?post=896"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/panel?post=896"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/language?post=896"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/age?post=896"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/duration?post=896"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/resource_type?post=896"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/audience?post=896"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/wf_post_folders?post=896"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}